Wyvern's extraction thimbles have been proven for their purity and consistent high quality. The thimbles are widely used in Soxhlet extraction units by companies such as FOSS, Gerhardt GmbH, Büchi and others providing a safe, convenient and efficient method of solvent extraction of solids and semi-solids.

Thimble sizes should be selected carefully to fit extractors correctly. The different sizes represent the established practice of showing the internal diameter and overall length of the thimble in millimetres. Therefore, an extra allowance for wall thickness should be made when calculating external diameters. The thimble should pass through the narrower end of the upper extractor socket, allowing 1-2 mm clearance, and be 5-10 mm above the level of the top of the siphon tube